Projection reflector lamp



Jan. 23, 1968 R. DAYTON V ETAL 3,365,664

PROJECTION REFLECTOR LAMP Filed Dec:' 1, 1965 7 DAVID R. DAYTON 4 7 ROBERT H. MAIN 4 Y ROBERT M. GRIFFIN IIN VEN'I 0R3 AT TORNE Y United States Patent ()fifice 3,365,604 Patented Jan. 23, 1968 Field of invention This invention relates to electric incandescent lamps of the reflector type, and particularly to those useful for projection purposes, such as in motion picture or slide projectors. It is especially useful in lamps utilizing a bowlshaped member having a reflector on its inner or concave surface, that is on the surface nearest the filament coil or other light source which is used with the projector.

Prior art Previous devices of this type have used a bowl-shaped member of glass, with a reflecting coating of a metal such as silver or aluminum on at least part of the concave surface, such as shown in United States patent application, Ser. No. 241,618, filed Dec. 3, 1962, by David R. Dayton et al., now Patent No. 3,250,939. In that device the rear shoulder of the expanded rim portion could be used as a reference member, with respect to which all optical parts were in a fixed relationship. The reference shoulder could be used for holding the bowl in position while the filament coil was being aligned, and in facilitating the proper positioning of the finished lamp in a socket. A narrow shoulder has been used on certain external reflectors designed to hold a small iodine quartz incandescent lamp, with the large diameter end of the reflector open rather than being sealed to a glass cover plate. The iodine quartz lamp itself is, of course, sealed hermetically.

If the shoulder around the bowl-shaped portion is narrow, it will disappear on sealing to a cover plate, while if the shoulder is large as in the application mentioned it may make the device too large for many purposes. A different means of aligning the lamp, or referencing it, was accordingly needed.

Summary of the invention The present invention solves the problem by molding three small protuberances or bumps spaced around the outside surface of the bowl-shaped portion of the glass envelope. When seating the filament mount to the reflector bowl, the bumps, if unevenly spaced, can serve to fix the orientation of the reflector about its axis, that is, to set the pattern of the bumps with respect to the meridian plane through the axis of the filament, especially if the filament is a coil having a straight axis. The base can subsequently be fixed to the lamp in such a position with respect to the bump pattern that the lamp will be properly aligned with respect to the filament when placed in a suitable socket for the base.

This could be done if the bumps were evenly spaced, because then the bowl could be set in any of three positions of orientation about the axis, which means about the filament. If the bumps are spaced around the circmnference at angles of 100 and 160, respectively, between successive bumps, they will be very effective for the purpose just mentioned.

Bumps can be placed in contact with a flat surface while the filament is being aligned and the filament will then be in proper position with respect to the bumps and to the surface along the axis of the reflector but will not have a fixed orientation about the axis of the reflector. Accordingly, the reflector is set on an annular conicalappearing metal piece, the conical surface actually being a surface of revolution slightly larger than the outside of the bowl-shaped portion, so as not to interfere with the action of the bumps, and having three dimples or recesses in its surface into which the bumps will fit and rest, fitting against the bottom of the recesses. In this way, the bowl-shaped portion will be fixed in position in said annular piece and will not wobble during adjustment of the filament coil in it.

Further description of the invention Other objects, features and advantages of the invention will be apparent from the following specification, taken in connection with the accompanying drawings, in which:

FIGURE 1 is an elevational view partly in section, of a lamp according to the invention when held in a device for adjusting the filament position;

FIGURE 2 is a bottom view of the bowl-shaped member showing the orienting protuberances on the outside of the bowl;

FIGURE 3 is an enlarged detail of the protuberances; and

FIGURE 4 is a perspective view of a completed lamp.

In FIGURE 1, the bowl-shaped portion 1 has the glass wall 2, with the protuberances 3, 4 and 5 shown also in FIGURE 2, and in more detail in FIGURE 3, spaced around it in a plane through the bowl 1 and parallel to the axis. Lead-in wires 6 and 7 are sealed through the glass stem 26 of said bowl-shaped member and support the tungsten wire filament 8, which is usually placed near the focus of the reflector coating 9, the latter being of silver, for example, deposited on the inner surface of the bowl member 1.

The bowl 1 is supported by the annular metal holder 19, whose inside surface 11 is shaped to be slightly longer than the outside of bowl-shaped member 1. The protuberances 3, 4 and 5 fit into the recesses or openings 12 in the inside surface 11 of metal holder 10. A stand 13 extends from holder 10, and may be aflixed to a convenient plate 14 by the supporting posts 13. The exhaust tube 27 of bowl 1 can extend through the plate 14, unless the legs 13 are long enough to support it above the plate 14.

The bowl therefore can be held closely in a fixed reference position while the filament 8 is manipulated by the movable end rod 15 of the micrometer 16 until the light from the filament is reflected to the proper spot. The micrometer 16 is held in arm 17 which is rotatable as shown by the arrow in FIG. 1, about pivot 18 in bracket 19 secured to post 20 in member 14.

A cover plate 21 is sealed to the bowl-shaped member 1 around the circumferences of each, and a base 22 affixed to bowl 1 with external contacts 23, 24 connected to lead-in wires 6 and 7 through flexible intermediate wires such as 25. The base 22 can be affixed by suitable high temperature cement or the like not shown, and can be lined up with respect to the protuberances 3, 4, 5 after the cement is applied and before it hardens. In this way everything is referred to, that is, lined up with respect to, these three protuberances, 3, 4, S and they serve as the elements about which everything critical is organized.

Although a particular embodiment is described above, various modifications will be apparent to a worker skilled in the art, without departing from the spirit and scope of the invention, which is set forth in the appended claims.

What we claim is:

1. A hermetically-scaled electric incandescent reflector lamp comprising: a bowl-shaped member, lead-in wires sealed through said member, an incandescible filament held by and electrically connected to said filament, a reflector coating on the inside surface of said bowl-shaped member to reflect light from said filament, three protuber- 3 ances on the outside of said bowl-shaped member, the filament and reflector coating having a predetermined relation to said protuberances, and a cover plate, the rim of the cover plate and bowl-shaped members being sealed together hermetically.

2. The invention according to claim 1 in which the protuberances are in a piane perpendicular to the axis of the bowl.

3. The invention of claim 1, and a base afiixed to said bowl in predetermined relationship to said protuberances.

4. The invention of claim 1 in which the protuberances are spaced unevenly from each other.

4 5. The invention of claim 1 in which the distances between successive protuberances is 100, 100 and 160 respectively.

References Cited UNITED STATES PATENTS 2,997,357 8/1961 Gaither 3l3-113 X JOHN W. HUCKERT, Primary Examiner.

10 A. I. JAMES, Assistant Examiner. 

1. A HERMETICALLY-SEALED ELECTRIC INCANDESCENT REFLECTOR LAMP COMPRISING: A BOWL-SHAPED MEMBER, LEAD-IN WIRES SEALED THROUGH SAID MEMBER, AN INCANDESCIBLE FILAMENT HELD BY AN ELECTRICALLY CONNECTED TO SAID FILAMENT, A REFLECTOR COATING ON THE INSIDE SURFACE OF SAID BOWL-SHAPED MEMBER TO REFLECT LIGHT FROM SAID FILAMENT, THREE PROTUBERANCES ON THE OUTSIDE OF SAID BOWL-SHAPED MEMBER, THE FILAMENT AND REFLECTOR COATING HAVING A PREDETERMINED RELATION TO SAID PROTUBERANCES, AND A COVER PLATE, THE RIM OF THE COVER PLATE AND BOWL-SHAPED MEMBERS BEING SEALED TOGETHER HERMETICALLY. 